Abstract 16056: Cardiac Stem Cell--Derived SDF-1 Contributes to Improved Myocardial Function Following Acute Ischemia/Reperfusion
Introduction: Cardiac stem cells (CSCs) improve myocardial function following ischemia via differentiation of CSCs into cardiomyocytes. But little is known about implication of paracrine action by CSCs in the improvement of cardiac function after injury. We hypothesized that 1) CSCs secrete potent paracrine factor(s) to facilitate better myocardial protection following acute ischemia/reperfusion (I/R) injury compared to differentiated CSCs (D-CSCs) and 2) SDF-1 is a vital paracrine factor for CSC-mediated cardioprotection.
Method: CSCs were isolated from C57BL/6 mouse hearts using a CSC isolation kit (Millipore). Characteristics of CSCs were identified by flow cytometry and mRNA-qPCR analysis. CSCs developed into D-CSCs after cultivation in cardiac differentiation medium (Millipore). Conditioned medium (CM) was collected from CSC or D-CSC cultures. Paracrine factors in CSC CM and D-CSC CM were assessed by cytokine antibody array. Cardiac I/R was performed in isolated mouse hearts via Langendorff (groups in bar graph). 0.1x106/ml cells or 1.5ml medium were infused immediately before ischemia in according groups. Data were analyzed with two-way ANOVA, p<0.05=statistically significant.
Results: Flow cytometry assay revealed that CSCs expressed Sca-1 (∼99%), CD29 (∼98%) and CD44 (∼90%), but did not express CD31, CD34, CD45 or CD106 (<5%). D-CSCs expressed lower levels of Sca-1 (60%) and no CD44 (<5%). Higher transcript levels of α-MHC, MLC2v and cTnT were detected in D-CSCs compared to CSCs. SDF-1 was noted in CSC CM, but not in D-CSC CM (graph). Infusion of CSC and CSC CM improved myocardial function following I/R, but treatment with D-CSC or CSC CM+SDF-1 blocker abolished CSC-mediated myocardial protection (bar graph).
Conclusion: CSCs improved I/R-injured cardiac function through the production of paracrine factor SDF−1. Paracrine protection was abolished during differentiation of CSCs towards cardiomyocytes due to lack of SDF-1 expression in D-CSCs.
- © 2010 by American Heart Association, Inc.